Hearing aids have been of great to benefit to individuals with hearing loss. A typical hearing aid includes: one or more microphones to pick up incoming audio sound (acoustic energy), an amplifier, and a speaker positioned to allow delivering an amplified acoustic signal into the user's ear. Unfortunately, feedback of the amplified acoustic signal back into the microphone can cause undesirable effects such as ringing or howling. The maximum amplification that can be provided by the hearing aid is typically limited by this feedback.
Various techniques have been applied to attempt to reduce problems caused by feedback to allow increased amplification. While, these techniques have provided varying success, as hearing aids are made smaller, problems caused by feedback have become increasingly challenging. In particular, as a hearing aid is made smaller, not only can the amount of acoustic feedback increase, but a smaller delay is present in the feedback path. The reduced delay and increased feedback can result in oscillation building to unacceptable levels much more quickly.